If one of the color components for fill color is not zero it is converted to one and does not show on white background which is usual for printing. Looks like spy ink. Can be seen only on non-white background

Fix: in _cairo_win32_printing_surface_show_glyphs() function for the block when source->type == CAIRO_PATTERN_TYPE_SOLID

replace the line 
opaque = cairo_pattern_create_rgb (GetRValue (color), GetGValue (color), GetBValue (color));
with
opaque = cairo_pattern_create_rgb (GetRValue (color)/255., GetGValue (color)/255., GetBValue (color)/255.);

arguments should be double in range 0.0-1.0